The Game:
After 27 rounds and two weeks of intense finals football, it's fitting that the season's best and most consistent sides will contest the grand final.

Western Sydney have stunned everyone by taking out the Premiers' Plate and are just one win away from securing am incredible double. Coach Tony Popovic does have some selection headaches though, with in-form winger Youssouf Hersi unavailable through suspension while key midfielder Aaron Mooy (knee) is racing the clock to prove his fitness.

Mooy was close to playing against Brisbane last weekend and is doing all he can to play. If Mooy is unavailable then teenager Yianni Perkatis - who has played just two Hyundai A-League games - is likely to get the nod in the centre of midfield. Kwabena Appiah-Kubi is expected to take Hersi's spot on the right. Defender Jerome Polenz (quad) is also rated a 50-50 chance for the Wanderers.

Central Coast are no strangers to grand final week, with the club getting set for their fourth decider in just eight seasons. But the club are still waiting to claim their first championship. Graham Arnold will be forced into one change with midfielder Nick Montgomery out after he was sent off in the semi-final win over the Melbourne Victory.

Oliver Bozanic is the logical replacement to partner skipper John Hutchinson in the centre of midfield. The two sides have met three times this season, with one win apiece and a goalless draw way back on the opening weekend of the season.

The big issue:
Wanderers - Western Sydney have built their season on hard work and a tremendous team ethic but it's arguable there is no more important player to their success than Hersi. To emphasise how much the Wanderers will miss the Dutch winger in the decider, you only have to know one stat - they have not won a match when Hersi has not played. Can they buck that trend and complete the double or is it a case of no Hersi, no championship for the Wanderers?

Mariners - A number of the current Mariners squad must still be having nightmares about how they let the 2011 Grand Final slip to the Brisbane Roar. It's been nothing but heartache for the club when it comes to A-League deciders and as much as they will try to play it down, it must play on their minds. They will need to get any negative thoughts out of their heads if they are to finally get success on the big day and banish their previous demons.

The game breaker:
Shinji Ono - Ono's team-mate Mark Bridge might have delivered in A-League grand finals before but it's the Japanese midfielder the Mariners defence will need to keep an eye on if they are to break their grand final hoodoo.

Ono oozes class and provides the extra bit of quality which has helped the Wanderers go all the way in their debut season. His goal against Brisbane last week is one of the best ever in the A-League finals and he will again be a key for the premiers on Sunday afternoon. The absence of Nick Montgomery means Mariners skipper John Hutchinson could be charged with the role of shutting down the former Japanese international.

Prediction: Wanderers 2-1 Mariners
Grand finals are always tough to predict but it's even harder to try and split these two sides. They are genuinely well-matched all over the park which will make for some intriguing one-on-one battles like the A-League's golden boot Daniel McBreen trying to break down the competition's stingiest defensive combination of Michael Beauchamp and Nikolai Topor-Stanley.

Then there's the Wanderers' leading-scorer Bridge looking to get the better of Mariners' brilliant right-back Pedj Bojic as well as the fierce battle in the middle of midfield. But this match could well hinge on which of the team's playmakers perform, with Ono vital to the Wanderers' hopes while Michael McGlinchey has been in career-best form for Central Coast.

After so many years of heartache you wouldn't begrudge the Mariners finally pulling through for a championship. But with a wave of momentum and huge groundswell of support, the Wanderers look good to complete a remarkable fairytale debut season.